In general, Colorado’s famed fourteeners—the state’s 54 peaks over 14,000 feet (4,267 meters) tall—are pretty easy to climb. This makes the east face of 14,259-foot (4,346-meter) Longs Peak in Rocky Mountain National Park, which serves up the biggest buffet of multipitch, big-wall routes this side of Yosemite, even more of a prize. The east face’s sheer, 2,000-foot-high (609-meter-high) Diamond is a true, big mountain adventure that requires confidence in climbing 5.10 rock and the guts to sleep out in a portaledge.

If you do not seek that gritty of a challenge, there are easier options on the east face, such as the 5.4 Kieners route, a classic alpine climb that wends around the south side of the Diamond and takes advantage of a snow-filled couloir. But it is the hard rock routes on the Diamond that bring alpinists here from across the globe. The most popular way up, the Casual Route (5.10a), is still quite committing. Plus, the 5.10 crux of the Casual Route is near the top so you need to keep your energy in reserve.

For even greater challenges, King of Swords (5.12a) is a tough, overhanging route, and Eroica (5.12b), which runs next to the Casual Route, provides continuous 5.11 climbing with two cruxes at 5.12. Technical talk aside, the Diamond may be the very best place in the Lower 48 to test your big-wall mettle with a guide before you move on to even bigger mountains. Of course there’s certainly no shame in the Diamond being the apex of your rock-climbing achievements.

Need to Know: Colorado Mountain School (www.totalclimbing.com) will guide you up the Diamond on one- or two-day trips, from $475.